1 files changed, 97 insertions, 0 deletions
diff --git a/spec/frontend/dirty_submit/dirty_submit_form_spec.js b/spec/frontend/dirty_submit/dirty_submit_form_spec.js
new file mode 100644
index 00000000000..d7f690df1f3
--- /dev/null
+++ b/spec/frontend/dirty_submit/dirty_submit_form_spec.js
@@ -0,0 +1,97 @@
+import { range as rge, throttle } from 'lodash';
+import DirtySubmitForm from '~/dirty_submit/dirty_submit_form';
+import { getInputValue, setInputValue, createForm } from './helper';
+
+jest.mock('lodash/throttle', () => jest.fn(fn => fn));
+const lodash = jest.requireActual('lodash');
+
+function expectToToggleDisableOnDirtyUpdate(submit, input) {
+  const originalValue = getInputValue(input);
+
+  expect(submit.disabled).toBe(true);
+
+  setInputValue(input, `${originalValue} changes`);
+  expect(submit.disabled).toBe(false);
+  setInputValue(input, originalValue);
+  expect(submit.disabled).toBe(true);
+}
+
+describe('DirtySubmitForm', () => {
+  describe('submit button tests', () => {
+    it('disables submit until there are changes', () => {
+      const { form, input, submit } = createForm();
+
+      new DirtySubmitForm(form); // eslint-disable-line no-new
+
+      expectToToggleDisableOnDirtyUpdate(submit, input);
+    });
+
+    it('disables submit until there are changes when initializing with a falsy value', () => {
+      const { form, input, submit } = createForm();
+      input.value = '';
+
+      new DirtySubmitForm(form); // eslint-disable-line no-new
+
+      expectToToggleDisableOnDirtyUpdate(submit, input);
+    });
+
+    it('disables submit until there are changes for radio inputs', () => {
+      const { form, input, submit } = createForm('radio');
+
+      new DirtySubmitForm(form); // eslint-disable-line no-new
+
+      expectToToggleDisableOnDirtyUpdate(submit, input);
+    });
+
+    it('disables submit until there are changes for checkbox inputs', () => {
+      const { form, input, submit } = createForm('checkbox');
+
+      new DirtySubmitForm(form); // eslint-disable-line no-new
+
+      expectToToggleDisableOnDirtyUpdate(submit, input);
+    });
+  });
+
+  describe('throttling tests', () => {
+    beforeEach(() => {
+      throttle.mockImplementation(lodash.throttle);
+      jest.useFakeTimers();
+    });
+
+    afterEach(() => {
+      throttle.mockReset();
+    });
+
+    it('throttles updates when rapid changes are made to a single form element', () => {
+      const { form, input } = createForm();
+      const updateDirtyInputSpy = jest.spyOn(new DirtySubmitForm(form), 'updateDirtyInput');
+
+      rge(10).forEach(i => {
+        setInputValue(input, `change ${i}`, false);
+      });
+
+      jest.runOnlyPendingTimers();
+
+      expect(updateDirtyInputSpy).toHaveBeenCalledTimes(1);
+    });
+
+    it('does not throttle updates when rapid changes are made to different form elements', () => {
+      const form = document.createElement('form');
+      const range = rge(10);
+      range.forEach(i => {
+        form.innerHTML += `<input type="text" name="input-${i}" class="js-input-${i}"/>`;
+      });
+
+      const updateDirtyInputSpy = jest.spyOn(new DirtySubmitForm(form), 'updateDirtyInput');
+
+      range.forEach(i => {
+        const input = form.querySelector(`.js-input-${i}`);
+        setInputValue(input, `change`, false);
+      });
+
+      jest.runOnlyPendingTimers();
+
+      expect(updateDirtyInputSpy).toHaveBeenCalledTimes(range.length);
+    });
+  });
+});